There
are no proofs in science - at least not strictly speaking. There are
in mathematics and logic.
In
basic terms, why is that?
This
is how John Horgan puts it:
“The
only propositions that can be verified – that is, proved true –
are those dealing in pure logic or mathematics.”
Horgan continues:
“Such
systems are closed, in that all their components are based on axioms
that are true by definition.” (202)
In
other words, such propositions can be proved because they belong to
systems which make it the case that they can be proved. Or, more
formally, they can be proved because they are "based on axioms that
are true by definition”. That basically means that the propositions
or theorems are provable – and sometimes easily so – precisely
because they're derived from axioms which are true by definition and
which, in turn, belong to systems entirely created by such axioms and
the following theorems; as well as by the deductive rules from which the
theorems are generated. That means, in essence, that proof is
possible because the axioms - which generate the theorems - were
designed to be true by definition. That truth-by-definition is
passed on (as it were) from the axioms to the theorems/propositions.
In
a simple sense, all this makes proof easy. Or at least in makes proof dependent only on systems and their contents – nothing more.
Truths
about 'external reality', on the other hand, depend on a whole lot
more and that's why they can never be proven. And that's as true of
scientific statements as it is of the statements of religion or
politics.
However,
it's proof that's being spoken of here, not truth
itself. Thus some of those scientific statements can be taken to be
true – just not provably true. (Indeed since Godel we have
known that some 'Godel sentences' within maths and logic are true;
though not provably true.)
Thus
truth and proof are intimately connected in logic and maths. Though
that's not the case with science; if only when taken separately from
its mathematical underpinnings.
As
for that 'external reality'. Horgan continues by saying that
“[n]atural systems are always open”. Moreover,
“our
knowledge of them is always incomplete, approximate, at best, and we
can never be sure we are not overlooking some relevant factors”
(202).
In
other words, natural systems aren't based on axioms which are true by
definition. They aren't human creations. Having said that, numbers
and logical relations can be deemed to be platonic/abstract in
nature; though the systems themselves are still human creations. It
is the abstractions and entities they capture that are – if they
are – platonic or mind-independent.
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